Tính (theo mẫu):
Mẫu \(\displaystyle 2\,:\,{3 \over 5} = {{2 \times 5} \over 3} = {{10} \over 3}\)
a) \(\displaystyle 3:{2 \over 7}\) b) \(\displaystyle 2:{1 \over 3}\)
c) \(\displaystyle 4:{9 \over 2}\) d) \(\displaystyle 3:{1 \over 4}\)
a) \(\displaystyle 3:{2 \over 7} = {{3 \times 7} \over 2} = {{21} \over 2}\) b) \(\displaystyle 2:{1 \over 3} = {{2 \times 3} \over 1} = 6\)
c) \(\displaystyle 4:{9 \over 2} = {{4 \times 2} \over 9} = {8 \over 9}\) d) \(\displaystyle 3:{1 \over 4} = {{3 \times 4} \over 1} = 12\)
-- Mod Toán lớp 4